It looks as though this installer gave a "haircut" to the conductors he landed on the 3-pole breaker at the bottom right of the photo. Because the conductors were too large to cram into the small terminals, the installer simply chopped off enough of the individual strands to make them fit.

 

Chopping the strands off could certainly create a "hot spot" on the wires, because they are no longer able to carry the full amount of current they were rated for. This could also be a violation of 210.19(A), if those chopped branch circuit conductors no longer have the ampacity required to serve the maximum load they serve. It is most definitely a violation of 110.14(A), which requires that wire connections to terminals must ensure "a thoroughly good connection" is made without damaging the conductors.

On the breakers in the upper part of the photo, you'll notice multiple conductors twisted together and jammed into the terminals. This would also be a violation of 110.14(A). The last paragraph of this section of the NEC requires terminals for aluminum conductors or more than one conductor to be identified as such.

Any of the lousy conductor terminations here could also be a violation of 310.15(A)(3), since they are being used or associated in a manner that could cause the temperature limits of the conductors to be exceeded.